Leak-off fuel collecting system for fuel injection engines



V. D. ROOSA April 1, 1958 LEAK-OFF FUEL COLLECTII IG SYSTEM FOR FUELINJECTION ENGINES Filed Feb. 28, 1955 INVENTOR VERNON 0 9003A ATTORNEYJLEAK-OFF FUEL COLLECTING SYSTEM FOR FUEL INJECTION ENGINES Vernon D.Roosa, West Hartford, Conn. Application February 28, 1955, Serial No.491,146 1 Claim. (Cl. 299"58) This invention relates to improvements infuel injection systems for internal combustion engines, and moreparticularly to an improved arrangement for collecting leak-01f fuelfrom the fuel injectors and fuel pump of such injection systems.

One object of the invention is to provide a leakage fuel collectionarrangement for fuel injection systems which is easy to install orremove without tools and which is adaptable for use with a variety offuel injection systems.

Another object is to provide such a leak-off fuel collecting arrangementfor fuel injection systems which is rugged and durable, yet simplifiedin construction and low in cost.

Another object is to provide an improved connector for use with such aleak-off fuel collecting arrangement which is cheap to make and easy touse, and which reduces the amount of metal tubing required.

Other objects will be in partobvious, and in part pointed out more indetail hereinafter.

The invention accordingly consists in the features of construction,combination of elements .and arrangement.

of parts which will be exemplified in the construction hereafter setforth and the scope of the application of which will be indicated in theappended claim.

In the drawing:

Figure 1 is a diagrammatic view of an engine and part of a fuelinjection system thereof, illustrating the general arrangement of aleak-off fuel collecting system construction in accordance with theinvention;

Figure 2 is an enlarged sectional view of a portion of a leak-01f fuelcollecting system similar to that shown in Figure 1; and

Figure 3 is a sectional view of the structure taken on line 3-3 thereof.

Referring to the drawing, Figure l is a diagrammatic view of an engineand part of a fuel injection system of the type with which the presentinvention is concerned. The engine 2 has a plurality of fuel injectors4, one for each cylinder, which are supplied with high pressure fuel bya fuel pump 6. The injectors are of the inwardly opening nozzle valvetype which inherently opcrate with a small amount of internal leakagepast the nozzle valve stem, and this leakage is collected and reofFigure l turned to the fuel tank 8 through a leak-off line 10 ineluding'a series of short lengths of metal tubing 12 extending between theinjectors. The leak-off line 10 may also extend to the fuel pump 6 toserve as a drain and return to the fuel tank for any leakage fueltherefrom.

Turning now to the details of the leakage-collecting system, as bestshown in Figure 2, the leakage in each injector 4 or in the fuel pump 6is collected within its casing 14 and led off through a centrally boredadaptor or nipple 16. The nipple 16 has a hollow cylindrical body 18threaded into casing 14 at one end and provided at its outer end with acentrally apertured head 20 of slightly enlarged diameter forming withthe body 18 2,829,004 Patented Apr. 1, 1958 "ice an annular radialshoulder 22. i The head of thenipple has a screw-driver slot 24 oralternatively may have wrench-engaging flats or a wrench-receivingsocket to facilitate threading of the nipple into the'injector or fuelpump casing 14.

Mounted on the outer end of each nipple 16 is a one-piece T-shapedconnector 30 of resilient material through which the leakage fuel fromthe nipple may flow to the leak-offline 10. The T-connector includes acentrally bored cylindrical stem 32 dimensioned to he slipped' over thehead of the nipple 16 with'a tight leakproof fit,

receive with a tight sliding leakproof fit a length of metal tubing 12forming a portion of the leak-off line 10. The connector may be made ofany suitable elastomer such as Buna N base neoprene which is imperviousto the fuel and capable of withstanding the temperatures encountered onthe exterior of the engine, and which will not stick to the metal of thenipple or tubing.

With this arrangement all that is required to conmeet up the leak-01fsystem once the nipples 16 are installed is to slide the stem 32 of aconnector 30 over the head of each nipple, and then slide the ends ofconnecting lengths of tubing 12 into the cylindrical bores 40 of theseveral connectors. Conveniently the unused bore 40 of the lastconnector in line 10 may be closed by inserting therein a plug 42dimensioned for a tight sliding leakproof fit. Since the resilience ofeach connector 30 enables it to grip the nipple and tubing with a tightsliding leakproof fit, there is no threading required in installingeither the connectors or the tubing, and no flanging of thetubing isrequired. Thus the system may be connected up or entirely detached byhand without using any tools. Moreover, each connector may be readilytwisted or bent back to facilitate inserting the ends of the lengths oftubing 12 into the bores 40 without bending the tubing, and hencerelatively stiff straight pieces of tubing, of minimum length sufficientto reach from one connector to the next, may be conveniently used toform the leak-off line 10 without danger of breakage or loss of fuel.

Thus it may be seen that a leak-01f fuel connecting system constructedas described may be quickly and easily installed or detached Withouttools, and is adaptable to a'variety of engine installations.Furthermore, the systern providessubstantial economies both in thereduced amounts of tubing required and in the inexpensiveness of theconnectors 30 themselves, and hence is substantially cheaper than priorart systems.

As many changes could be made in the above construction and manyapparently Widely different embodiments of this invention could be madewithout departing from the scope thereof, it is intended that all mattercontained in the above description or shown in the accompanying drawingsshall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the language used in the followingclaim is intended to cover all of the generic and specific features ofthe invention herein described and all statements of the scope of theinvention which, as a matter of language, might be said to falltherebetween.

I claim:

In a leak-off fuel collecting arrangement for the fuel injection systemof an internal combustion engine, a

a 3 short projectingnipple on each fuel injector having a cylindricalbody terminating at its outer end in an em larged head forming with thecylindrical body an annularradial shoulder, said nipple having a centralbore forr'ningan outlet' fo'r leak-off fuel, a one-piece resilientT-con'nect'or halvinglan integral cylindrical stemjpiro vidd with adaxial bore dimensioned tobe' slipped over the head of each nipple with atight sliding leakproof fit and terminatingin an inturned cylindricalbead hooked under said radial shoulder and engaging said cylindricalnipple body, said T-connector having an integral laterally extendinghead provided with lateral cylindrical bores at its opposite endscommunicating with the bore of said stem, and straight sections of metaltubing joining said connectors having a greater length than the distancebetween the heads of the T-connectors and being dimensioned to be pushedinto said lateral bores with a tight sliding leakproof fit, saidT-connectors being sufiiciently resilient to permit lateral flexingthereof to facilitate insertion of the ends of saidtubing.

References Cited in the file of this patent UNITED STATES PATENTS2,436,815 Lum Mar. 2, 1948 2,594,639 Gossett Apr. 29, 1952 2,706,134Wilson Apr. 12, 1955

